A. Field of the Invention
The invention generally relates to methods, systems and apparatus for removal of a contaminate from an aqueous medium. More specifically, the invention provides methods, systems and apparatus for minimizing back-pressure in an adsorption material constrained within a housing, the adsorption material used to remove contaminates from a flowing aqueous medium.
B. Background Art
Cities and towns throughout the world depend on having clean potable water. The dependence on clean potable water has increased as the population of the world has increased, especially as industrial use of fresh water resources have become commonplace. Increased industrial use of fresh water resources has resulted in a corresponding deterioration of water quality throughout the world, due partly to industrial related release of contaminates into the water. In addition, contaminates are also naturally present in various fresh water resources, for example, high uranium content in fresh water resources throughout areas of Colorado, New Mexico and Texas.
The decrease in water quality is contravening to the world's increased dependence on clean potable water supplies, requiring a concerted effort toward both minimizing the release, and removing existing contaminates, from water supplies throughout the world (whether the contaminates are natural or released as industrial pollution).
Conventional water treatment facilities are often equipped with specialized systems for removal of specific contaminates from a water supply. For example, water treatment facilities can be equipped to contact the water supply with an affinity material having sorptive qualities toward a specific contaminate. Typically, these sorptive materials are constrained in a column, or other like housing, that receives the water source, treats the water source, and passes the water source back to a traditional water treatment facility.
A number of target contaminates can be removed from a water source when contacted to a sorptive material. For example, removal of uranium from an aqueous medium has previously been described in U.S. Provisional Patent Application No. 60/619,369, filed Oct. 15, 2004.
Conventionally, removal of contaminates using sorptive materials is often accomplished through the use of down- or up-flow media adsorption. Aqueous medium is released onto the adsorptive material and flows through the material in a given direction. One problem facing the water treatment industry is the clogging of these large volume housing units with suspended particulates in the aqueous medium. Clogged adsorption material leads to increased pressures required to “force” the water through the adsorption and particulate material. The clogging ultimately results in more costly water treatment and shut down to either replace the adsorption material or to perform costly backwash, where the aqueous medium and clogging particles are forced through and out of the column in the opposite direction of normal flow, carrying the particulates out of the column for disposal.
In particularly problematic cases, the particulates have a low level of radioactivity, for example, the particulates may have a low amount of uranium. When radioactive particulates are concentrated within an adsorption material they often must be disposed of at a low level radioactive repository. In contrast, under normal flow through conditions, the radioactive material in the particulates is often at such low concentrations, that it is allowed to pass onto the end user of the water, to a sewer system, or to a water treatment facility.
Against this backdrop the present invention was developed.